In U.S. Pat. No. 5,278,912 and U.S. Pat. No. 5,488,668, audio compressors for use in hearing aids are disclosed. Such compression systems may work individually on a number of frequency bands.
In EP 0′ 590′ 903 B1 an output limiter for hearing aid amplifiers is disclosed.
In EP 0′ 836′ 363 B1, a loudness limiter is disclosed, by means of which the loudness of a signal transmitted to the human ear by a hearing apparatus can be restricted to a maximum acceptable loudness level.